The overall objective of this research is to study the physiological aspects of amino acid fermentations by clostridia. We propose to continue our investigations of molar growth yields and growth yield coefficients obtained with Clostridium sporogenes and Clostridium sticklandii growing with various amino acids as primary sources of energy and carbon. Concurrently, we anticipate measuring adenylate energy charges in cells of these bacteria growing at various rates and correlate these with growth yield data. Studies of the regulation of enzymes involved in the interconversion of proline and glutamate will be continued.